Posted
by
Soulskill
on Friday October 29, 2010 @12:53PM
from the going-full-drake dept.

The Bad Astronomer writes "A recent astronomical report (abstract in Science) came out stating that as many as 1 in 4 sun-like stars have roughly earth-mass planets. But are they habitable? A simple bit of math based on some decent assumptions shows that there may be billions of potentially habitable worlds in the galaxy. '... astronomers studied 166 stars within 80 light years of Earth, and did a survey of the planets they found orbiting them. What they found is that about 1.5% of the stars have Jupiter-mass planets, 6% have Neptune-mass ones, and about 12% have planets from 3 – 10 times the Earth’s mass. This sample isn’t complete, and they cannot detect planets smaller than 3 times the Earth’s mass. But using some statistics, they can estimate from the trend that as many as 25% of sun-like stars have earth-mass planets orbiting them!' Getting to them, of course, is another problem altogether..."

It's great that we could expand to many different planets. The leap between the Moon, Mars and an extra solar planet is so enormous though that the only thing this tells us is that we may be able to more closely identify where we should listen to for signals.

The High Frontier, Redux [antipope.org] - Covers the true scale of the distance between planets, and the energy requirements of going between them. He estimates that sending an Apollo-sized capsule to the nearest star would take as much energy as is produced on Earth in a year.

The distances are astronomical (ha ha). There's no economic gain at this point to going to the stars. Heck, we've barely stepped off our own rock.

Still, one would like to think that right now we're beginning the surveying aspects of future interstellar exploration, and as soon as the physicists deliver us bountiful amounts of cheap energy and some useful way around the speed of light, we will be better able to pick the targets.

With cryo-stasis ships, at least there's a reason to eventually settle somewhere. You want to wake up (or stop taking watches) and eventually start your new life. You can bear the hardships of the journey, because you have a personal goal that you intend to some day fulfill.

The thing about generational ships, is that if they're really self-sufficient and comfortable enough that the early generations don't go mad, then what's the point of landing anywhere? You can say that humans need to expand, but the people onboard won't be able to meet that need, and they're just going to have to cope with such a limited existence. But if they succeed, then that culture will be passed down, so you'll have a whole population that is happy staying in their little box. How can you plan so far into the future and keep the plan intact?

There's a Star Trek episode ("The World is Hollow And I Have Touched the Sky") where the people don't even know they're on such a ship, and the more I think of it, the more realistic and believable that seems. People wouldn't ever be able to stick to such a long-term mission in which they don't personally have any stake, so they might as well not be depended upon to achieve it, or even know it's happening. One single centralized authority with infinite patience (a computer) and a secret and tyrannical agenda, is about the only thing that could keep it going.

I thought about his pretty often, and I think that the most reasonable form of generation spacecraft would be AI controlled, self-repairing, self-sustaining, and very huge, so that Earth-like landscapes could be built in them. A ship that is 1000 km wide and high, and 10,000 km long would not be much different from a planet to its inhabitants. Clarke's 1x4x9 ratio also would make a reasonable form factor. Such a ship can of course only be built when resources are mined from the solar system planets, especia

given the choice to expand out into a entire planet I doubt there would be any society that would turn it down.

Oh, I agree with that. It seems like an easy decision for the final 3 or 4 generations ("We're almost there! Keep going!" and "Yippee, we're here!"). But a few dozen generations before that? I can imagine people saying, "Why spend our energy on the acceleration/deceleration rockets? Let's pump it into the holodeck instead."

Our materials technology has going to have to advance considerably. The only way some of the equipment like the Voyager probes have survived is because they are, relatively speaking, extremely simple with very low energy requirements.

You start talking multi-generation biosphere ships or cryo ships you're talking about a huge set of problems that go hand in hand with maintaining an isolated spacecraft for centuries or thousands of years, without meaningful help or even raw materials to be used to fix proble

Agreed, the focus in these discussions always seems to be on how to move the spaceship but in reality that is a minor problem with several plausible solutions. When it comes to keeping the crew alive we don't even know how to keep a biodome [wikipedia.org] on Earth from turning into a rotting cesspit after a year or two. Once we know how to do that we can perhaps use the technology to fix the (human) life support systems on "spaceship Earth" before we send a handfull of explorers to look at other planets.

Who said anything about it still working? The issue was about the energy requirements for getting objects to other star systems, not within any particular timeframe. Voyager will almost certainly survive until it reaches another star system; maybe not with any power, but it'll be an intact object (there aren't a lot of other objects floating around in interstellar space for it to collide with).

Voyager will almost certainly survive until it reaches another star system; maybe not with any power, but it'll be an intact object (there aren't a lot of other objects floating around in interstellar space for it to collide with).

That what bothers me the most. The trend around the world is to cut money where there is no immediate return, everyone wants a quick buck.
A nation's future is in the investment they put in research and science.
But who am i to be listened to, when big corps have a hold on all the elected officials ?

Private spaceflight is a lot more promising than NASA is. Especially if the goal is to find new habitable planets. With private spaceflight, every dollar is a dollar towards a goal. With NASA its a nickel towards a goal and 95 cents spent on pointless bureaucracies.

Cut funding to NASA, allow private space companies to use the R&D, blueprints and the like and watch us achieve heights that NASA never dreamed of.

Private spaceflight has a lot of inducement to figure out how to get stuff into earth orbit, and not very much at all to go anywhere beyond that. Trust me, I know NASA people, scientists and non-scientists. They are not pointless bureaucrats. They really want to go to the stars.

They may "really want to go to the stars" but it isn't going to happen with a government program. Government programs are/always/ plagued by waste and inefficiencies. The only reason why they can sometimes get things done is because they have infinite money from stealing from taxpayers. I guarantee you if you gave private spaceflight the information and the like that NASA has and a budget that they could get stuff done faster and more efficiently than NASA could. The only reasons why we don't have private

Do you have any numbers to support this? Although government programs generally are horribly inefficient, do you have any actual data indicating that NASA is just as bad? You seem to be relying on the assumption that government programs are always wasteful inefficient messes to the nth degree. Private spaceflight seems like an interesting idea, and I know there are several companies already working towards it, but reaching another star is a long, long, long term investment. It seems to me that government funding is actually useful in cases where there is no immediate return for the investors. Otherwise, you're essentially relying on philanthropy, no?

a) Private, commercial ventures are also always plagued by waste and inefficiencies. Humans are involved. You get what you get.b) Just because there's waste doesn't mean it's 95% waste. That's like saying that because lightbulbs emit both heat and light, they're incapable of ever illuminating anything.c) Grandiose statements like this one, common on the right, are faith-based attacks. It's common sense. Everyone knows governments waste. Everyone knows governments are nothing but wasteful bureaucracies. It's obvious. Duh. The only good government is a tiny one. But not nonexistent, as that might be seen as disparaging the founding fathers.

The underlying assumption is that you can only trust someone who wants to take your money for his own profit, because anything else is too good to be true. But not too much profit. So you can only trust someone who wants to take your money for his own profit in a suitably competitive market. You only trust greedy people. And then...

The only reason why they can sometimes get things done is because they have infinite money from stealing from taxpayers.

d) No. They're not stealing. We're pooling our moneys to achieve a common goal, as we've agreed to do, through the system of laws we've previously agreed to. If you don't like it, go live in France. (I can say this because I got tired of being told to live in France when I bitched about our new motherland security overlords after 9/11.)

Government restrictions.

e) That's what it *does*. That is the function of government. All freedoms not taken away, we keep. You're complaining that they're doing their job? If not, we need to know the specific restrictions you disagree with; honestly, I trust them to have a better idea of what restrictions we need than I trust you. They have thousands of people looking at what can go wrong when some private individual decides it's perfectly safe to shoot a rocket off from his back yard to go colonize Mars. And those thousands of people? They're just private citizens, like you and me, raised in the same country, under the same flag, learning the same constitution, going to the same backyard BBQ's. They love freedom too. Freedom not to be blown up because of their neighbor's stupid belief that freedom only means something when they can be perfectly reckless.

The main reason is that NASA is the primary agency studying climate change, or at least it was until the Republicans in congress started cutting funding for the necessary satellites and research because they were concerned that they might prove global warming was real sufficiently that their constituents would start getting concerned. Or really continue failing to disprove global warming.

It's what happens whenever you let Sophists have access to the controls over research.

With NASA its a nickel towards a goal and 95 cents spent on pointless bureaucracies.

Sometimes bureaucracies really are pointless. Other times they're the only way you can manage something as vast and multi-generational as interplanetary/interstellar spaceflight. I fear that the pro-privatization Slashdot crowd will learn this to their chagrin in a decade or two.

Right now there are functioning NASA probes at the edge of our solar system that are nearly as old as I am (a gracefully aging 34, thank you).

The beauty of the system is, you could always go build one of the "big corps" and get listened to, or spend all your money on pursuing space travel, rather than grouse about how other people won't fund your science fiction fantasies.

Privatize NASA. Take 100% of the funding that is going to NASA right now, and create a huge series of X-Prizes, and we'll have the rest of the system colonized within a few decades, and we'll likely have our first probes headed toward the nearest star with potentially habitable planets on the same time scale.

Once we confirm "M-class" planets, we'll be ready to send manned probes.

That would seem to make Fermi's paradox even more troubling. My bet is that abiogenesis is vanishingly improbable. It seems pretty reasonable to be fairly optimistic about every other term in Drake's equation.

I wonder what happens if we continue to expand our knowledge about exoplanets at the current rate but we don't discover life on another planet by the year 2100. Fermi's Paradox bugs the hell out of me. I can't see how we are unique... but I also can't see why the evidence of other civilizations wouldn't be obvious.

I wonder what happens if we continue to expand our knowledge about exoplanets at the current rate but we don't discover life on another planet by the year 2100. Fermi's Paradox bugs the hell out of me. I can't see how we are unique... but I also can't see why the evidence of other civilizations wouldn't be obvious.

There are loads of reasons.

1. How long did it take for US to come about? That's a fairly long period of time for a planet to remain habitable. Cut that time down, and you drastically reduce the chance that something like 'us' will come about.

2. What good is intelligence to life? To us, it is necessary, to life? Not really. Algae and bacteria do just fine (and bacteria in some sense can be considered immortal!) Life COULD be plentiful, and intelligent life could well be so rare that it is unique.

3. Consider what we are able to see. We can basically see forms of electromagnetic radiation. That's not too useful for picking out little bits of information that would clue us in to someone else sending out information. Our emmanations are already decreasing (if considered per-capita) We can get more done with less power via directional antennas, better electronics, and now, fiber and direct access communications. We might just not see them.

4. Interstellar travel cost compared to opportunity is well... astronomical. Barring imaginary physics, the only point to go to another planet/star is to colonize it.

Think about it, we human beings are the absolute kings of colonization. We have set foot and abode on nearly every inch of this planet in some form or scope. And even if you argue that our grasp in some areas is tenuous, it certainly isn't due to lack of drive to colonize. We ARE wanderers and travelers, but to even consider something like interstellar travel is daunting to us. Is it so surprising that something which would restrict a human from traveling would also daunt another form of life?

It's not too much of a stretch to consider that our existance is every unique even without resorting to some sort of religious justification.

If it took our planet 4-5 billion years to produce 'us', and the universe is only 14 billion years old, we aren't dealing with much time for starting over. A single asteroid collission at the wrong time and the death of a human progenitor could very well mean 4 billion years of life development resulted in no intelligent life on Earth. It is not some sort of evolutionary goal.

All valid points. Also all speculation... just like my thoughts:) That is why I put the "Year 2100" out there. I would certainly think that if there is life to discover that we would have found it after a century of looking. This assumes we continue to grow in our capabilities at the astonishing rate we have seen over the past twenty-or-so years.

Barring imaginary physics, the only point to go to another planet/star is to colonize it.

We have sent probes to all the planets in our system, have landed in two of them. Once we have some way to send a probe to another star system you can bet we will.

We are quickly reaching a turning point in economics when manufacturing is so cheap that we will not be restrained by the cost of things. Looking at the world today, the richest countries do not bother to manufacture things anymore, that can be outsourced. Wit

Could be God.
Consider: what is more unlikely? That before time there was an infinitely dense concentration of something that burst, creating everything we observe?
Or that before time, there was something else that said, "I'll make something today" and created everything we observe?
I don't consider either one more or less plausible than the other.

That would seem to make Fermi's paradox even more troubling. My bet is that abiogenesis is vanishingly improbable. It seems pretty reasonable to be fairly optimistic about every other term in Drake's equation.

We won't really know until we can detect earth mass planets, but from what I've been seeing, I believe that our planet is the equivalent of hitting the galactic jackpot.

Specifically, our huge moon. The impact that did that must of created a sort of 'second stirring', resulting in a climate different than that of Venus and Mars.

I have no problems believing that habitable planets are more than a thousand ly apart, much less habitable planets that develop sapient, tool using life forms. Right now, that's outside of our detection range. Even SETI has a range of only like 60ly, if I remember right.

Well, there's the Jungle Hypothesis, the Zoo Hypothesis, and I'm sure a few other ones. While lack of proof isn't proof, there's also the possibility that intelligent life in this part of the galaxy only started recently.

Apes or angels. If there is other sentient life out there the cosmological timescale makes it a high probability that most of it is either so primitive that it can't have an interplanetary impact of any kind, or so ludicrously advanced that it wouldn't give a rat's ass about a bunch of monkeys who are really impressed with how they can move things around by burning stuff. We're either going to be like a PhD looking at an ant hill or they are. Either way we're probably safe, unless we run into an adolescent god with a magnifying glass, like Trelane "The Squire of Gothos".

For me the exciting part is that, we can actually try to have a decent estimate for some of the terms in the Drake equation.
A hint to the answer of just how improbable (or probable) abiogenesis is, may be found right here in our solar system. By searching for life on Mars, Europa, etc.
Just another reason not to slash the NASA budget.

It seems pretty reasonable to be fairly optimistic about every other term in Drake's equation.

f = the fraction of the above that actually go on to develop life at some pointfi = the fraction of the above that actually go on to develop intelligent life

I've always found these 2 to be the ones that I have trouble being optimistic about. Just because a planet CAN support life doesn't mean that it definately will. And just because life forms, it doesn't always develop intelligence (see Dinosaurs and Ancient Marine Reptiles).

We've only got ONE case study so far where this has occured, us. I have trouble b

It seems pretty reasonable to be fairly optimistic about every other term in Drake's equation.

Actually, there's one other you can be pessimistic about, and it has pretty depressing implications for us: the fraction of technological societies that get off-planet. Two big humps here:

Agression: Any species that fights its way to intelligence and technological dominance of its planet will be about as aggressive as we are. A species that is not good at stepping over what's in its way to get the resources necessary for survival is a species that doesn't survive. This raises the question: can a dominant technological species avoid destroying itself with the advanced weaponry it develops (or even inadvertently by triggering an ecological collapse) before it gets off-planet? The jury is still out on whether we'll manage that...

The Lotus-Eater Problem: About the time a dominant technological species starts to develop the necessary skills to get off-planet, it likely also start to develop the skills necessary to create *really good* simulations of reality that are "just like the real thing." Can a culture avoid the lure of just abandoning themselves in fantasies which can be made more exciting and fulfilling than anything in the real world?

Perhaps true, but it is not a satisfying answer to Fermi's paradox. Tippler and others have made good arguments for colonization/exploration by robotic probes, which we also have no evidence of. Maybe it's evidence that strong AI is exceedingly difficult?

We assume we're unique because we haven't found anything else like us. Does that make sense?

One circle of life existed 65 Million years ago for far longer than we have been alive and yet they didn't develop the intellect to construct anything. We look at the other parts of life around us that are just beginning to use tools - but they're still a long ways away from reaching where we were a million years ago.

Given that we've only been able to study these two sample cases, and both suggest that we're "above a

We look at the other parts of life around us that are just beginning to use tools...

Actually I would put forth that we are just really really good at killing anything that might even remotely be a (tool using) competitor. Take Neanderthals for example; they had cave art, tools, and bigger brains than us, and I'd guess that we are a big reason why they no longer exist.

It's also recently been suggested by a study saying that about 1-4% of our DNA is Homo neanderthalensis - so even had THEY been the dominant species it's likely that 1-4% of their DNA today would be Homo Sapien.

Either way you slice it, any of the intelligent species on Earth appear to have a common ancestor. So whether we killed off other intelligent forms of life and thats why there aren't any is moot: none of the other animal kingdoms have shown anything along the scale that humans have, or else we'd be c

However, the qualities of this planet that make it suitable for life aren't as simple as "well, look at it!"

The entire planet has gone through several phases of development (molten, crusty, wet, snowball, volcanic, tropical, tectonic, plus some not-so-planet-killer asteroid impacts) to shape what is now its ecology, and it's not showing any signs of being static yet.

So it would be egregiously inept, given this knowledge, to assume that other planets with sap

Or extinct before we manage to even get the tech to leave.We're not even building decent space stations. To me the priorities should be to build a space station that humans can live on "indefinitely". Not waste money on going to Mars.

When you have developed space stations on which people can live on indefinitely, you don't have to rush to Mars. In fact Mars becomes a lot less important economically. The asteroids would be more interesting- build space colonies from the asteroids. From that point you would b

That's all well and good, but what are we going to do when the wavefront of gamma & x-rays from stars falling into the black hole at the center of the galaxy reaches us? Then what are we going to do?!!!

Habitable seems to be in the eye of the beholder. Does it mean if we dropped off a human on the surface, he would be able to breathe? Does it mean that it is roughly the right mass? The right mass and roughly the right temperature? Right mass, temperature and has an atmosphere? All the above and has bountiful liquid water?

I am very excited about our discoveries over the past decade or so. But it will be another before we can truly have a reasonable idea of how many planets are "habitable".

Well, a surface that doesn't immediately kill us while we wear minimal life support apparatus would be a good start. Even if we can't breath the air, being able to wear regular clothing and no bulky gloves would be a big step up.

This reminds me of Geico commercials. "15 minutes could save you fifteen percent or more on car insurance." If you think about that sentence, it really doesn't say anything. The sentence would be true if 1 in 10,000 people who took 15 minutes to call Geico saved more than fifteen percent off their car insurance.
I hate to be the cynical guy, but this really seems like a bit of a fluff story. The criteria for "potentially habitable" seems to pretty low, relying primarily on planet mass and distance from

This reminds me of Geico commercials. "15 minutes could save you fifteen percent or more on car insurance." If you think about that sentence, it really doesn't say anything. The sentence would be true if 1 in 10,000 people who took 15 minutes to call Geico saved more than fifteen percent off their car insurance.

My personal favorite example of such claims has always been "baked with real vegetables" on some snack crackers.

In no way does that imply that the vegetables are ingredients. Merely that they were b

Lets say there are billions of inhabited planets. Then they should be popping into a passing black hole or be blown away for an intergalactic highway project now and then. But I have never felt a disturbance as though millions of voices suddenly cried out in terror and were suddenly silenced. How come?

That is almost exactly what I came here to post. Until we identify a second body in the universe that supports life (whether in this solar system, or not and whether that life is there because we put it there or it came from some other source), it is premature to estimate how many planets in the galaxy are habitable.

You can put an Earth-sized planet where Pluto is and that's not going to mean anything. Assuming they mean "habitable" from the perspective of humans, the appropriately-sized planet must also be at the sweet spot distance from the Sun for moderate temperatures, have a moon to stabilize rotation for normalized weather patterns, and also produce a strong enough magnetosphere to protect an atmosphere. This is completely ignoring a lot of other factors that come into play as well, but the bottom line is I think it's a little premature to start designating M-class planets.

Am I the only one that remembers the episode where Sagan talks about this? You can apply all the stats and variables to this, but you can only get a general idea... We (in our lives) will probably never get to anywhere near 1% accuracy of how many habitable planets are out there. Its all theory.

This is such a stupid article. It doesn't take into account atmosphere or presence of water at all. The only data the the guy uses is that there happens to be one planet 20 light years away that is roughly the same size as Earth. That is the only data he uses to come to his conclusion. What a waste of time.

We keep making this a huge deal, but somehow I feel that when we do find life in other planets somehow it will not be this interesting.
It will be like finding a new crawling reptile in the Amazon.
Besides, even if we do find signs of life in a planet light years away, how much will we be able to learn about them? Space travel hasnt really taken off, we dont even have cheap and reliable means of going to the moon!

You take a number which you don't know very well, so you estimate it. Then multiply it by a factor which you really don't know, so you just guess that. Next you multiply the result by another number which you may never know, so you just pull that one out of/dev/random, and multiply them all together.

are pointless. its like reading a phonebook, and the subject matter fails to entice anyone...

now, had Carl Sagan so much as uttered the first sentence of a comment he heard related to the summary? My jaw would drop, my eyes would glass over,
and I would spend the next three hours digging through the mess in the garage trying to find my old telescope and praying for some miraculous cavalcade of
ineffably grandiose funding for NASA.

Having a large gas giant to shield the Earth from excessive meteors is thought to be a major factor in the habitability of Earth. So even if we take those numbers at face value and assume that 25% of solar systems have an Earth-like planet, only those that have a Jupiter-like planet (1.5%) are candidates for life. Further assuming those two are independant variables, that drops the odds of finding life down to.375% without even accounting for other contributing factors like having liquid water or a significant moon.